From grape berries to wine: population dynamics of cultivable yeasts associated to “Nero di Troia” autochthonous grape cultivar

Abstract

The aim of this work was to study the biodiversity of yeasts isolated from the autochthonous grape variety called "Uva di Troia", monitoring the natural diversity from the grape berries to wine during a vintage. Grapes were collected in vineyards from two different geographical areas and spontaneous alcoholic fermentations (AFs) were performed. Different restriction profiles of ITS-5.8S rDNA region, corresponding to Saccharomyces cerevisiae, Issatchenkia orientalis, Metschnikowia pulcherrima, Hanseniaspora uvarum, Candida zemplinina, Issatchenkia terricola, Kluyveromyces thermotolerans, Torulaspora delbrueckii, Metschnikowia chrysoperlae, Pichia fermentans, Hanseniaspora opuntiae and Hanseniaspora guilliermondii, were observed. The yeast occurrences varied significantly from both grape berries and grape juices, depending on the sampling location. Furthermore, samples collected at the end of AF revealed the great predominance of Saccharomyces cerevisiae, with a high intraspecific biodiversity. This is the first report on the population dynamics of 'cultivable' microbiota diversity of "Uva di Troia" cultivar from the grape to the corresponding wine ("Nero di Troia"), and more general for Southern Italian oenological productions, allowing us to provide the basis for an improved management of wine yeasts (with both non-Saccharomyces and Saccharomyces) for the production of typical wines with desired unique traits. A certain geographical-dependent variability has been reported, suggesting the need of local based formulation for autochthonous starter cultures, especially in the proportion of the different species/strains in the design of mixed microbial preparations.

Challenges of the Non-Conventional Yeast Wickerhamomyces anomalus in Winemaking

“…As a minor species, P. membranifaciens was described as part of the indigenous population during spontaneous fermentations of wines in Mendoza, Argentina [38]. Yeast diversity studies of grape varieties from vine-growing regions of China identified P. fermentans and Pichia guilliermondii [39], and the former was also isolated from a Southern Italian autochthonous grape cultivar [40]. P. kluyveri and Pichia farinosa were found in vineyards and grape musts from four production regions of South Africa, although they were not the predominant species [41].…”

Microbial Resources and Innovation in the Wine Production Sector

“…The second step, an in-bottle fermentation of a base wine with sugar, is followed by an ageing period in which the wine is in contact with dead yeast cells (Kemp et al, 2015). There are several factors that affect the final organoleptic quality, such as grape variety, vineyard management, quality of the base wine and the yeast strain inoculated in the second fermentation (Pozo-Bayón et al, 2010;Pérez-Magariño et al, 2015;Garofalo et al, 2016b). However, the evolution of the second fermentation and the ageing of the wine are of particular importance because they enhance the organoleptic properties of the base wine, giving the sparkling wine its characteristic aroma and flavour, foam ability and roundness.…”

Use of Autochthonous Yeasts and Bacteria in Order to Control Brettanomyces bruxellensis in Wine

“…Autochthonous yeast strains isolated from the Apulia Region located in Southern Italy were: S. cerevisiae KT029756, KT029757, KT029758 [32] Candida zemplinina KT029748 [32], Hanseniaspora uvarum KT029770 [32], Hanseniaspora guilliermondii KT029766, Torulaspora delbrueckii KT029800 [32], Metschnikowia pulcherrima KT029783 [32] and Brettanomyces bruxellensis Unifg 8 [4]. In addition, one indigenous strain of Oenococcus oeni Unifg 21 [41] was also used.…”

“…A recommended strategy to avoid this problem and reduce the time between AF and MLF is the co-inoculation of the malolactic starter culture with the yeast [4,29,30]. Among the starter cultures, many investigations have studied the microbial biodiversity in a regional area in order to select autochthonous starters denoted by different oenological characteristics [31,32] since these microorganisms are potentially adapted to a definite grape must and reflect the "terroir" of a particular area [31,33].…”